1. Field of the Invention
The present invention relates to a laterally diffused metal-oxide-semiconductor (LDMOS) transistor and a manufacturing method thereof, and more particularly, to an LDMOS transistor used for improving breakdown voltage and a manufacturing method thereof.
2. Description of the Prior Art
Laterally diffused metal-oxide-semiconductor (LDMOS) transistor has become a common semiconductor power device and has been widely applied to power converters, power amplifiers, switches or rectifiers because of being able to endure high breakdown voltage, have good switching efficiency and operate under a low resistance. In addition, the LDMOS transistor has planar structure, which is easy to be produced and to be integrated with the current semiconductor technology, so that the production cost of which is reduced. Generally, the drain of the LDMOS transistor is electrically connected to the high voltage during operating. Thus, in the conventional LDMOS transistor, an insulation structure is designed to be disposed between the drain and the gate to endure the high electric field generated by the high voltage and avoid the LDMOS transistor from breaking down. However, the high electric field may be concentrated at the adjacent area of the drain, the insulation structure and the well region, which limits the breakdown voltage of the LDMOS transistor. Therefore, it is a common goal in this field to provide an LDMOS transistor and a manufacturing method thereof with high breakdown voltage.